Defending the Campus Perimeter with Audio

• By Detrick Ellis
• September 18, 2023

In early June, a woman was arrested after she was found on a runway at George Bush Intercontinental Airport (IAH) in Houston. The woman allegedly slipped under a gate at the airport’s perimeter and ran onto the airport tarmac before she was caught and arrested. It was the second time in two weeks that someone on foot has gotten onto the IAH airport property and reached the tarmac, said a news report. Days before, a 26-year-old man was arrested for jumping a fence and trying to stow away on a flight.

Whether it’s an airport or a college campus, perimeter security breaches are not rare. It’s difficult to protect large areas of an airport. Yet, those facilities are secured with large fences.

Securing a college or K–12 campus perimeter can be more difficult, given the fact that the environment is (mostly) open to students, visitors, and staff. Even more, defining a college perimeter can be confusing and challenging as the college or university expands.

Yet, perimeter security (when done well) can stop or deter crime or malicious activity before it enters onto your premises. As such, it is a solid first line of defense in keeping a K–12 or college campus secure and a focus for security teams.

The Importance of Audio

Technology within the security industry to mitigate threats at the perimeter has adapted to numerous changes through the years, from the early days of analog devices to today’s IP intercoms, networked cameras, and access control solutions—in addition to VMS solutions, analytics, cloud-based products, virtual security guards, and more.

Yet, no matter what security technology is in place, the need for clear communication always remains from audio and HD voice solutions.

How can audio from intercoms and IP speakers play a role with perimeter security?

For instance, at a K–12 school entrance, video intercom solutions can identify parents and visitors and help school staff and security teams quickly determine if the individual should enter the school, or not.

At the school’s outer areas, IP public address speakers are easy to install and offer excellent two-way communications, in all conditions. School security teams, using video surveillance, can see an individual trying to enter the school perimeter and determine, through audio, why they are there or direct them to leave.

Emergency stanchions can provide a visual and audio indicator to help security teams to identify visitors and vendors outside of a school’s entrances and exit points. They can also be used within school parking lots, far from entrance and exit areas. Once activated by the user, campus security can see and hear who wants access to the school.

At exterior fences and gates, which may still be on school property but a distance away from a school’s entrances, intercom solutions with HD audio can be mounted on the fence to help school security teams to identify individuals from a distance.

The benefits of audio at the perimeter are numerous.

First, it means that your security solution is interactive. Security teams talk and listen to the person that’s seen on a video surveillance system, via the intercom, no matter where the location or where an individual is on school grounds. A clear voice and sound clarify the intent behind the images that are captured on a camera and increases situational awareness.

Audio can detect voices, noises, or other sounds that are not within direct view of a video camera. Those sounds can be analyzed by a security team, and action can be taken before the individual gets to the school doors.

Adding audio also means that a security officer and the person in front of the camera at the intercom can interact, even when that individual is at outer perimeters—which, if they have ill intent, is where you want them to stay until your security team can arrive on scene. That data, which goes beyond video surveillance images, can be shared between security, police, emergency services and more. Your security team is now providing first responders with actionable data for a more effective response and a strategy to mitigate future incidents.

The Importance of Clear Audio

It’s exciting to witness the rapid growth of audio technology’s importance in security operations that mitigate security threats and enable faster response on K–12 and college campuses.

Yet are all those devices delivering crystal-clear audio? Is the need for users to be clearly heard and understood being met, every time?

Strong, crystal-clear voice communications are possible in any environment, but it requires the right combination of hardware, software, and mechanics.

The Right Hardware

An intercom’s hardware combination of amplifier, speaker, and microphone must be robust enough to withstand extreme environments and deliver audio loud enough to overcome all background noise. Any outdoor communication device should incorporate a digital MEMS microphone, allowing audio to be consistently translated into 1’s and 0’s, regardless of extreme temperatures or moisture. A Class-D, 10W amplifier delivers more than 95dB, louder than a semitruck or subway train. And with an amplifier that powerful, a matching 10W speaker is crucial to avoid distortion at high volumes.

The Right Software

With IP technology, audio processing software can be deployed directly in the edge device to create the best intelligibility. Noise Reduction technology removes background noise so that the operator can clearly hear the caller. Native, Onboard Acoustic Echo Cancellation prevents feedback and enables full Open Duplex communication, where both people can talk at the same time, and be understood. Devices should also intelligently adjust to the environment; Automatic Gain Control will take a voice that is too loud or too weak and level it out to an undistorted and clear signal. Automatic Volume Control will raise the speaker volume, so it is always loud enough to be heard.

The Right Mechanics

The mechanics of an intercom are important, as well. A traditional, vandal-resistant intercom speaker design uses two overlapping stainless-steel plates, which trap the sound waves between them and create distortion, especially at higher volumes. Instead, the speaker grill should incorporate an anechoic, circular design where there’s no reflection of sound waves as they pass through the station’s faceplate. The result is crystal-clear audio, even at the loudest volume. Unfortunately, loud volume creates significant vibration, so the speaker grill should be die-cast into a rigid aluminum frame and the microphone surrounded by a dampening material, to protect against the transfer of any sound vibrations. All these mechanical elements work together to produce strong, distortion-free, intelligible voice audio.

Only this combination of hardware, software, and mechanics will ensure clear audio and clear communications. When you understand how intelligible audio is achieved, then you can find the communications solution that will reliably allow you to hear, be heard, and be understood, every time.

Every K–12 and campus school security team faces increasingly complex threat environments, especially at their perimeters. Audio solutions via intercoms and IP speakers are the solution to providing intelligence and communications and to securing those perimeters.

This article originally appeared in the September / October 2023 issue of Campus Security Today.